from math import hypot

x1, y1, x2, y2 = list(map(float, input().split()))

print("{:.8f}".format(hypot(x2-x1, y2-y1))) from math import hypot x1, y1, x2, y2 = list(map(float, input().split())) x1 list(map(float, input().split())) list map(float, input().split()) map float input().split() ().split () input split y1 x2 y2 print("{:.8f}".format(hypot(x2-x1, y2-y1))) print "{:.8f}".format(hypot(x2-x1, y2-y1)) "{:.8f}".format "{:.8f}" format hypot(x2-x1, y2-y1) hypot x2-x1 x2 x1 y2-y1 y2 y1 y1, x2, y2 = list(map(float, input().split())) list(map(float, input().split())) y1 y2 = list(map(float, input().split())) list(map(float, input().split())) y2 x1, y1, x2, y2 = list(map(float, input().split())) list(map(float, input().split())) x1 x2, y2 = list(map(float, input().split())) list(map(float, input().split())) x2
from math import hypot

x1, y1, x2, y2 = list(map(float, input().split()))

print("{:.8f}".format(hypot(x2-x1, y2-y1)))